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| Titel: |
POLYMERIZATION BY PHASE TRANSFER CATALYSIS. 27. SYNTHESIS OF POLYESTERS CONTAINING SILICON OR GERMANIUM. INFLUENCE OF THE BASE CONCENTRATION |
| Auteur: |
Tagle, L. H. Diaz, F. R. Nunez, M. Canario, F. |
| Verschenen in: |
International journal of polymeric materials |
| Paginering: | Jaargang 52 (2003) nr. 4 pagina's 287-294 |
| Jaar: |
2003-04 |
| Inhoud: |
Polyesters derived from diphenols containing Si or Ge and isophthalic and terephthalic acids dichlorides have been synthesized using phase transfer conditions, and characterized by spectroscopic methods. Two phase transfer catalysts and three molar ratios NaOH/diphenol were used, and the results evaluated by the yields and the inherent viscosity values; these are compared with those obtained without catalyst. When the catalysts were used there was an increase of the yields and the η inh values, due to the effectivity of the phase transfer process. Also, when the base concentration was increased, there was an increase of the yields due to a salting out effect which permits a higher transference of the diphenolate to the organic phase in which the reaction takes place, and an increase in the amount of the polyesters and, to a lesser extent, the molecular weight. There was no influence of the higher NaOH concentration on the stability of either the acid dichloride or the polyesters. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 85 van 131 gevonden artikelen
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